This standard specifies ultrasonic acceptance levels 2 and 3 for full penetration welded joints in ferritic steels, which correspond to GB/T 19418 quality levels B and C. An acceptance level corresponding to GB/T 19418 quality level D is not included in this standard as ultrasonic testing is generally not requested for this weld quality.
These acceptance levels are applicable to testing carried out in accordance with GB/T 11345.
This standard applies to the examination of full penetration ferritic steel welds, with thicknesses from 8 mm to 100 mm. It can also be used for other types of welds, materials and thicknesses above 100 mm, provided the examinations have been performed with necessary consideration of the geometry and acoustic properties of the component, and an adequate sensitivity can be employed to enable the acceptance levels of this standard to be applied. The nominal frequency of probes used in this standard is between 2MHz and 5MHz unless attenuation or requirements for higher resolution call for other frequencies. The use of these acceptance levels in conjunction with frequencies outside this range needs to be considered carefully.
2 Normative References
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 11345 Non-destructive testing of welds - Ultrasonic testing - Techniques, Testing Levels, and Assessment (GB/T 11345-2013, ISO 17640: 2010, MOD)
GB/T 19418 Arc-welded Joints in Steel - Guidance on Quality Levels for Imperfections (GB/T 19418-2003, ISO 5817: 1992, IDT)
GB/T 29711 Non-destructive Testing of Welds - Ultrasonic Testing - Characterization of Indications in Welds (GB/T 29711-2013, ISO 23297: 2010, IDT)
3 Measurement of Indication Length
The length of an indication shall be obtained through fixed echo amplitude level technique by measuring the moving distance of the probe along the length over which the echo amplitude is above the evaluation level, using the fixed echo amplitude level technique specified in Annex B.
